carry weight

Pole vault

Pole vaulting is an athletic field event in which a person uses a long, flexible pole (which today is usually made either of fiberglass or carbon fiber) as an aid to leap over a bar. Pole jumping competitions were known to the ancient Greeks, as well as the Cretans and Celts. It has been a full medal event at the Olympic Games since 1896 for men and since 2000 for women.

History

Poles were used as a practical means of passing over natural obstacles in marshy places such as provinces of Friesland in The Netherlands, along the North Sea, and the great level of the Fens of Cambridgeshire, Huntingdonshire, Lincolnshire and Norfolk. Artificial draining of these marshes created a network of open drains or canals intersecting each other. In order to cross these without getting wet, while avoiding tedious roundabout journeys over bridges, a stack of jumping poles was kept at every house and used for vaulting over the canals. Pole vaulting has been used by Venetian punters for moving to the shore from their boat. It has continued to be a folklore activity with annual competitions. Fierljeppen or broad-jumping with the pole, though the original form of the sport, has never found its way into global competition, the high jump being the only form recognized.

Modern competition began around 1850 in Germany, when pole vaulting was added to the exercises of the Turner gymnastic clubs by Johann C. F. GutsMuths and Frederich L. Jahn. The modern pole vaulting technique was developed in the United States at the end of the nineteenth century. In Great Britain, it was first practiced at the Caledonian Games. Initially, vaulting poles were made from stiff materials such as bamboo or aluminum, pole vaulting success was also originally measured by distance rather than height as it is today. Later, the introduction of flexible vaulting poles made from composites such as fiberglass or carbon fiber allowed vaulters to achieve new heights. Physical attributes such as speed and agility are essential to pole vaulting effectively, but technical skill is an equally if not more important element. The object of pole vaulting is to clear a bar or stick supported upon two uprights without knocking it down.

Modern vaulting

Today, athletes compete in the pole vault as one of the four jumping events in track and field. It is also the eighth event in the decathlon. During a competition, a bar progression is chosen by an event official. The progression goes from an initial height, called the opening height (presumably a height that all competitors are capable of clearing), and progresses higher by even increments. Once the competitor enters at a certain height, he has three attempts to clear the bar. If the vaulter clears, even if the vaulter missed one of his attempts, he gets three fresh attempts at the next height. At any time, a vaulter may decide to pass on a height, coming in at a higher one. If a vaulter has used any of his attempts on the height he decided to pass, he takes those attempts with him and has fewer attempts on the higher height. A "no height", often denoted "NH", refers to the failure of a vaulter to clear any bar during the competition.

Having cleared the highest height, the last competitor remaining in the competition wins. Vaulters are placed first, second and so forth according to their highest cleared height and the number of attempts that were taken to clear that height. A tie can occur when two or more vaulters have the same number of misses at every height. Ties can be broken in what is known as a jump-off. A jump-off is a sudden death competition in which both vaulters attempt the same height, starting with the last attempted height. If both vaulters miss, the bar goes down by a small increment, and if both clear, the bar goes up by a small increment. A jump-off ends when one vaulter clears and the other misses.

The equipment and rules for pole vaulting are similar to the high jump. Unlike high jump, however, the athlete in the vault has the ability to select the horizontal position of the bar before each jump and can place it between 0 and 80 cm beyond the back of the box, the metal pit that the pole is placed into immediately before takeoff. If the pole used by the athlete dislodges the bar from the uprights a foul attempt is ruled, even if the athlete himself has cleared the height. An athlete does not benefit from quickly leaving the landing pad before the bar has fallen. There is an exception to this rule if the vaulter is vaulting outdoors and has made a clear effort to throw the pole back, but the wind has blows the pole into the bar; this counts as a clearance. If the pole breaks during the execution of a vault, the competitor will be allowed another attempt.

Poles are manufactured with ratings corresponding to the vaulter's maximum weight. Some organizations forbid vaulters to use poles rated below their weight as a safety precaution. The recommended weight corresponds to a flex rating that is determined by the manufacturer by placing a standardized amount of stress on the pole and measuring how much the center of the pole is displaced. Therefore, two poles rated at the same weight are not necessarily the same stiffness. Because pole stiffness and length are important factors to a vaulter's performance, it is not uncommon for an elite vaulter to carry as many as 10 poles to a competition. The effective properties of a pole can be changed by gripping the pole higher or lower in relation to the top of the pole. The left and right handgrips are typically about shoulder width apart. Poles are manufactured for people of all skill levels and body sizes, with sizes as small as 2.3 m feet to more than 6.4 m, and rated for vaulters weighing under 40 kg to over 100 kg.

Pole vault technology

Competitive pole vaulting began using bamboo poles. As the heights attained increased, the bamboo poles gave way to tubular steel, which was tapered at each end. Today's pole vaulters benefit from poles produced by wrapping sheets of fiberglass around a pole mandrel (pattern), to produce a slightly pre-bent pole that bends more easily under the compression caused by an athlete's take-off. Different fiberglass types, including carbon-fiber, are used to give poles specific characteristics intended to promote higher jumps. In recent years, carbon fiber has been added to the commonly used E-glass and S-glass preimpregnation materials in order to create a pole with a lighter carry weight.

As in the high jump, the landing area was originally a heap of sawdust or sand where athletes landed on their feet. As technology enabled higher vaults, mats evolved into bags of large chunks of foam. Today's high tech mats are solid pieces of foam usually 1-1.5 meters thick. Mats are growing larger in area as well, in order to minimize any risk of injury. Proper landing technique is on the back or shoulders. Landing on the feet must be trained out of the athlete, to eliminate the risk of spraining or breaking an ankle.

Rule changes over the years have resulted in larger landing areas and additional padding of all hard and unyielding surfaces.

The pole vault crossbar has evolved from a triangular aluminium bar to a round fiberglass bar with rubber ends. This is balanced on standards and can be knocked off when it is hit by a pole vaulter.

Phases of pole vaulting

Although there are many techniques used by vaulters at various skill levels to clear the bar, the generally accepted technical model can be broken down into several phases, listed and described below:

The approach

The approach consists of the vaulter sprinting down the runway in such a way as to achieve maximum speed and correct take-off position upon reaching the pit. The pole is usually carried upright to some degree at the beginning of the approach, then gradually lowered as the vaulter gets closer to the pit. By doing this the vaulter can use the potential energy stored from carrying the pole upright to his advantage. It is common for vaulters to use long, powerful strides at the beginning of the approach, then accelerate by increasing stride frequency while maintaining the same stride length. Unlike short sprinting events such as the 100 m in which a forward lean is used to accelerate, vaulters maintain a a more upright torso position throughout the approach in order to maximise the height of their centre of gravity at takeoff.

The plant and take-off

The plant and take off is initiated typically three steps out from the final step. Vaulters (usually) will count their steps backwards from their starting point to the box only counting the steps taken on the left foot (vice-versa for left-handers) except for the second step from the box, which is taken by the right foot. For example; a vaulter on a "ten count" (referring to the number of counted steps from the starting point to the box) would count backwards from ten, only counting the steps taken with the left foot, until the last three steps taken and both feet are counted as three, two, one. These last three steps are normally quicker than the previous strides and are referred to as the "turn-over". The goal of this phase is to efficiently translate the kinetic energy accumulated from the approach into potential energy stored by the elasticity of the pole, and to gain as much initial vertical height as possible by jumping off the ground. The plant starts with the vaulter raising his arms up from around the hips or mid-torso until they are fully outstretched above his head, with the right arm extended directly above the head and the left arm extended perpendicular to the pole (vice-versa for left-handed vaulters). At the same time, the vaulter is dropping the pole tip into the box. On the final step, the vaulter jumps off the trail leg which should always remain straight and then drives the front knee forward. As the pole slides into the back of the box the pole begins to bend and the vaulter continues up and forward, leaving the trail leg angled down and behind him.

The swing and row

The swing and row simply consists of the vaulter swinging his trail leg forward and rowing, pushing, his top arm down to the hips, while trying to keep the trail leg straight, once in a "U" shape the left arm hugs the pole tight to efficiently use the recoil within the pole. Effectively, this causes a double pendulum motion, with the top of the pole moving forward and pivoting from the box, while the vaulter acts as a second pendulum pivoting from the right hand. This action results in even more potential energy being stored in the pole, all of which will be returned to the vaulter in later phases. The swing continues until the hips are above the head and the arms are pulling the pole close to the chest. From there the vaulter shoots his legs up over the cross bar while keeping the pole close.

Alternate swing methods

Another form of swing is called the double leg drop. After executing a normal take-off, the vaulter lets his lead leg drop and swings with both legs together. In doing this, the weight of the vaulter's lower body is centered further from his rotational axis, making it more difficult for the vaulter to swing with as great a speed as with a single legged swing. For the same reason, a vaulter with constant rotational speed will load the pole with more energy using a double legged swing than a single legged swing. Because the slower swing can make it more difficult for a vaulter to get in position for the rockback, the double leg drop is typically not taught as the conventional method. A successful double leg drop is exemplified by French vaulter Jean Galfione.

A third form of swing is called the tuck and shoot. This is accomplished by tucking both legs in toward the chest rather than leaving the trail leg extended. This has the opposite effect of the double leg drop: it shortens the lower body about the rotational axis, making the swing faster, but lessening the pole-loading effect of the swing. Because a shorter rotational axis can make it more difficult to use larger poles than with a longer axis, the tuck and shoot is also not considered the conventional method. A successful tuck and shoot is exemplified by former American record-holder Jeff Hartwig.

The extension

The extension refers to the extension of the hips upward with outstretched legs as the shoulders drive down, causing the vaulter to be positioned upside down. This position is often referred to as "inversion". While this phase is executed, the pole begins to recoil, propelling the vaulter quickly upward. The hands of the vaulter remain close to his body as they move from the shins back to the region around the hips and upper torso.

The turn

The turn is executed immediately after or even during the end of the rockback. As the name implies, the vaulter turns 180° toward the pole while extending the arms down past the head and shoulders. Typically the vaulter will begin to angle his body toward the bar as the turn is executed, although ideally the vaulter will remain as vertical as possible. A more accurate description of this phase of the vault may be "the spin" because the vaulter spins around an imaginary axis from head to toe.

The fly-away

This is often highly emphasized by spectators and novice vaulters, but it is arguably the easiest phase of the vault and is a result of proper execution of previous phases. This phase mainly consists of the vaulter pushing off of the pole and releasing it so it falls away from the bar and mats. As his body goes over and around the bar, the vaulter is facing the bar. Rotation of the body over the bar occurs naturally, and the vaulter's main concern is making sure that his arms, face and any other appendages do not knock the bar off as he goes over. The vaulter should land near the middle of the foam landing mats, or pits, face up.

The pole vault is exciting to watch because of the extreme heights reached by competitors, and the inherent danger of the activity, two elements which combine to make it popular with spectators.

Terminology

The following are terms commonly used in pole vault:

Bar: This is the cross bar that is suspended above the ground by the standards.

Box: A trapezoidal indentation in the ground with a metal or fiberglass covering at the end of the runway in which vaulters "plant" their pole. The back wall of the box is nearly vertical and is approximately 8 inches in depth. The bottom of the box gradually slopes upward approximately 3-feet until it is level with the runway. The covering in the box ensures the pole will slide to the back of the box without catching on anything. The covering's lip overlaps onto the runway and ensures a smooth transition from all-weather surface so a pole being planted does not catch on the box.

Drive knee: During the plant phase, the knee is driven forward at the time of "takeoff" to help propel the vaulter upward.

Grip: This is where the vaulter's top hand is on the pole. As the vaulter improves his grip may move up the pole incrementally. The other hand is typically placed shoulder-width down from the top hand. Hands are not allowed to grip the very top of the pole (their hand perpendicular to the pole) for safety reasons.

Jump foot: This is also referred to as the take-off foot. The jump foot is the foot that the vaulter uses to leave the ground as he begins his vault.

Pit: The mats used for landing in pole vault.

Plant position: This is the position a vaulter is in the moment the pole reaches the back of the box and the vaulter begins his vault. His arms are fully extended and his drive knee begins to come up as he jumps.

Pole: The fiberglass equipment used to propel the vaulter up and over the bar. One side is more stiff than the other to facilitate the bending of the pole after the plant. A vaulter may rest the pole on his arm to determine which side is the stiff side.

Standards: The equipment that holds the bar at a particular height above the ground. Standards may be adjusted to raise and lower the bar and also to adjust the horizontal position of the bar.

Steps: Since the box is in a fixed position, vaulters must adjust their approach to ensure they are in the correct position when attempting to vault.

Swing leg or trail leg: The swing leg is also the jump foot. After a vaulter has left the ground, the leg that was last touching the ground stays extended and swings forward to help propel the vaulter upwards.

Volzing: A method of holding or pushing the bar back onto the pegs while jumping over a height. This takes amazing skill, although it is now against the rules and counted as a miss. The technique is named after U.S. Olympian Dave Volz, who made an art form of the practice and surprised many by making the U.S. Olympic team in 1992.

6 metres club

The so-called "6 metres club", which consists of pole vaulters who have reached at least 6 metres (converts to 19' 8¼") , is very prestigious. In 1985 Sergey Bubka became the first pole vaulter to clear 6 metres; he also holds the current outdoor world record at 6.14 metres, set on 31 July 1994 in Sestriere.

All "6 metres club" members are men. The only woman to exceed 5 metres is Russian women's world-record holder Yelena Isinbayeva, who reached that height in 2005 and who has in total broken the outdoor women's world-record 24 times culminating in her current world record of 5.05 metres obtained in 2008 at the Beijing Summer Olympic Games.